The present invention relates to the general field of samplers and is particularly concerned with a sediment sampler.
Increased concerns for environmental issues has led to a concurrent demand for improved environment monitoring methods and devices. Some of the environment monitoring methods are based upon the monitoring of the sedimentation of bodies of water. Indeed, both suspended and bottom sediments may prove to be a valuable source of information related to the ecological health of various types of bodies of water such as streams, rivers, lakes, pounds or the like.
In particular, because of the major repercussions resulting from increased levels of bottom sediment it is highly desirable to evaluate and monitor the impact on the level of sediments created by the construction of man-made structures adjacent certain types of bodies of water such as streams or rivers. The dumping of numerous waste forms in shallow water, as well as dredging and other engineering activities, places large quantities of sediments and polluting substances in suspension. These substances are subsequently carried away to different parts of the water body by the action of currents. Many problems related to waste disposal, channel and harbor dredging, off shore drilling and other engineering projects required detail knowledge of the motion of suspended sediments.
Some of the problems generated by increased sediment density directly affect various life forms. For example, in it is well known that sedimentation may proved to be detrimental to the reproduction cycle of certain types of fish. Indeed, during the mating period, some fish species typically dig a nest in the gravel forming the bed of some rivers. Once the nest has been digged the eggs are laid and covered with a layer of gravel by the fish. Survival of the fish eggs requires proper oxygen supply. This oxygen supply is normally supplied by the flow of water through the gravel.
If the quantity of fine sediment increases adjacent the nesting region the oxygen supply to the eggs may suffer. Indeed, relatively fine sediments have a tendency to lodge in the gravel bed and to potentially block the through flow of water. Reduced water flow in the gravel, in turn, prevents adequate oxygen supply to the fish eggs. Since fine sediments often remain in the gravel for several years the problem often persists with sometimes important consequences.
Some prior art devices specifically designed for monitoring bottom sediments have been proposed in the prior art. However, most of these prior art devices suffer from several major drawbacks. For example, one prior art method involves the use of a bucket-type container or a bag filled with sampling gravel and buried in the riverbed. After a predetermined period of time the contains of the bucket or bag is removed and washed in order to evaluate the type and quantity of sediments that have settled in the sampling gravel. This method however only provide a rough estimate of sediment accumulation since sediments that would reach the sampling volume through lateral movement instead of vertical dropping are excluded. Also, these prior art devices may be sealed of by the dropping sediments.
Furthermore, the prior art devices also often suffer from the fact during withdrawal from the sampling area some of the sediments have a tendency to fall out of the sediment sampler hence, again affecting the accuracy of the sampling procedure. Still further, some prior art sediment samplers are particularly difficult to anchor to the bottom surface of bodies of water in such a manner that they remain stable during the sampling period. Accordingly, there exists a need for an improved sediment sampler.
In accordance with an embodiment of the invention, there is provided a sediment collecting device for collecting sediments in a body of liquid, the body of liquid defining a top surface and a bottom floor, the device comprising: a collecting container, the collecting container defining a collecting container base wall and a collecting container peripheral wall extending from the collecting container base wall, the collecting container peripheral wall being provided with a collecting aperture extending therethrough; an obstructing means positioned substantially adjacent the collecting aperture for selectively obstructing the collecting aperture, the obstructing means being movable between an open configuration allowing the sediments to flow through the collecting aperture and a closed configuration preventing the sediments from flowing through the collecting aperture; an anchoring means attached to the collecting container for anchoring the collecting container to the bottom floor of the body of water.
Preferably, the collecting container peripheral wall has a generally frustro-conical configuration and is provided with a plurality of collecting apertures extending therethrough, the collecting apertures being configured, sized and positioned so as to allow though flow of the liquid across the collecting container peripheral wall.
Conveniently, the device further comprises a carrying container configured and sized for receiving the collecting container, the carrying container defining a carrying container base wall and a carrying container peripheral wall extending from the carrying container base wall, the carrying container peripheral wall defining a carrying container peripheral edge; the device further including a carrying container lid, the carrying container lid being attachable to the carrying container upper peripheral edge for forming together with the collecting container a collecting enclosure, the carrying container lid being also attachable to the collecting container base wall for forming at least part of the anchoring means.
Preferably, the carrying container lid is attached to the collecting container base wall by a generally elongated attachment component extending through both the collecting container base wall and the carrying container lid, the attachment component protruding outwardly from the carrying container lid so as to form at least part of the anchoring means.
Conveniently, the obstructing means includes an obstructing container, the obstructing container being configured and sized so as to be at least partially insertable into the collecting container, the obstructing container defining an obstructing container base wall and a peripheral obstructing wall extending from the obstructing container base wall, the obstructing wall being provided with a valve aperture extending therethrough, the valve aperture being configured, sized and positioned so that when the obstructing means is in the open configuration the valve aperture is at least partially in register with the collecting aperture and so that when the obstructing means is in the closed configuration preventing the valve aperture is offset relative to the collecting aperture.
Preferably, the device further comprises a positioning means for facilitating the positioning of the obstructing means between the closed and open configurations and a localizing means for facilitating the localization of the device when the latter is immersed in the body of liquid.
Advantages of the present invention include that the proposed sediment sampler provides a novel and improved device for measuring the sedimentation in bodies of water such as oceans, lakes, estuaries, lagoons, reservoir and the like. The proposed device is specifically designed so as to increase the accuracy of the sampling procedure.
Also, the proposed sediment sampler is designed so as to allow the sampling of sediments traveling in at least two generally perpendicular directions. The proposed sediment sampler allows for the collection of sediments dropping substantially vertically towards the bottom of the body of water as well as for the collection of sediments that are traveling in a direction substantially parallel to the bottom of the body of water.
Furthermore, the proposed sediment sampler is specifically designed so as to reduce the risks of losing trapped sediments during removal of the sediment sampler on the sampling site and during transportation of the sediments to remote locations such as an analyzing laboratory. The proposed sediment sampler is further specifically designed so as to facilitate its installation at the sampling site and its removal from its sampling site through a set of simple and ergonomic steps without requiring special tooling or manual dexterity.
Also, the proposed sediment sampler is provided with anchoring features that allow the sediment sampler to be stably anchored to the bottom of the body of water therefore reducing the risk of having the sediment sampler washed away from the sampling site during the sampling period.
Still further, the proposed sediment sampler is specifically so as to be easily located once installed at the sampling site. It is also designed so as to be reusable and easily washable. Furthermore, the proposed sediment sampler is also designed so as to reduce required storage space when not in use.
Furthermore, the proposed sediment sampler is designed so as to conform to conventional forms of manufacturing therefore providing a sediment sampler that is economical, long lasting and relatively trouble free in operation.